Typically, vehicles are classified into various types based on a proposed use, a driving method, a shape, etc. Recently, there has been an increase in public attention drawn to the use of mini buses, vans, recreation vehicles, etc., as compared to the traditionally favored passenger cars, big sized buses, and vehicles for simple freight purpose.
Many automakers have exerted more efforts towards manufacturing various types of vehicles to meet customers' demands. In particular, many vehicles have been manufactured including appropriate modifications for export such that the vehicle meets various related regulations and tax systems of the importing countries.
For example, in the case of a 1-ton mini bus, the preference of the high roof vehicle has been increased in the EU and Middle America regions. In a one country, for example, in the case of a van, when an indoor floor space index of the interior of a freight compartment meets a certain regulation, a certain tax advantage is provided to the owner of a van. In a certain country, the floor space index is regulated by the sate law.
Therefore, under the above conditions, a method for expanding a sufficient indoor floor space index is to change a ceiling structure of a vehicle to a high roof structure. In the above vehicle, a certain container-shaped high roof having a certain inner space, not a curved or plane roof panel shape, is adapted.
Namely, a certain container-shaped high roof having a certain inner space is covered on a ceiling part of the vehicle body for thereby increasing the height of a vehicle body, and a sufficient indoor floor space index is obtained.
According to Japanese patent laid-open Nos. 2000-33820, Hei 9-254815, Hei 11-20736, and Sho 63-240477, in order to obtain a desired strength in a high roof structure, a flat steel plate is press-formed and fixed to a vehicle body by spot welding and thereby integrated with a vehicle body. In another method, the steel flat plate is rotation-fixed using a hinge point.
However, when a high roof formed of a steel-pressed flat part is used as in the conventional art, increasing an indoor floor space index of a vehicle is greatly limited due to a limit in a panel formation (it is difficult to form a container-shaped high roof having a desired depth). In addition, it is also difficult to comply with a regulation in certain countries.
Therefore, what is needed is to develop a high roof structure for a vehicle capable of providing a sufficient durability and strength for a ceiling part and achieving a desired indoor height of a vehicle body.